Tykerb has been approved by the FDA for use in conjunction with the chemotherapy drug Xeloda. Tykerb is a cancer medication that more precisely targets tumors without killing lots of healthy cells in the process.
Herceptin and Tykerb target a protein called HER-2/neu but work in different ways. Herceptin targets the outside of the HER2 protein and Tykerb works from the inside of the cell. This difference can give advanced breast cancer patients another drug to switch to if Herceptin stops working for them.
Glaxo said that Tykerb will be available in two weeks. The results of a study showed that Tykerb worked so well that the international study was stopped early and all the participants were offered the drug.
The FDA said it was too early to know if women taking Tykerb and Xeloda would live longer than those taking the latter drug alone.
Dr. Steven Galson, FDA drugs chief, said "Today's approval is a step forward in making new treatments available for patients who have progression of their breast cancer after treatment with some of the most effective breast cancer therapies available."
1. Cells are the most basic structure of the body. Cells make up tissues, and tissues make up organs, such as the lungs or liver. Each cell is surrounded by a membrane, a thin layer that separates the outside of the cell from the inside.
For a cell to perform necessary functions for the body and respond to its surroundings, it needs to communicate with other cells in the body. Communication occurs through chemical messages in a process called signal transduction. The purpose of these signals is to tell the cell what to do, such as when to grow, divide into two new cells, and die.
Targeted cancer therapies use drugs that block the growth and spread of cancer by interfering with specific molecules involved in the process by which normal cells become cancer cells (carcinogenesis) and tumor growth. By focusing on molecular and cellular changes that are specific to cancer, targeted cancer therapies may be more effective than current treatments and less harmful to normal cells.
However, monoclonal antibodies are "large" molecules. These very large molecules don't have a convenient way of getting access to the large majority of cells. Plus, there is multicellular resistance, the drugs affecting only the cells on the outside may not kill these cells if they are in contact with cells on the inside, which are protected from the drug. The cells may pass small molecules back and forth.
Exciting results have come from studies of multitargeted tyrosine kinase inhibitors, "small" molecules that act on "multiple" receptors in the cancerous cells, like Tykerb and Sutent. Drugs that inhibit/interfere with specific molecules. Basically inhibits various kinases, a type of enzyme that transfers phosphate groups from high-energy donor molecules to specific target molecules. Because they inhibit "multiple" kinases, it possesses activity against "multiple" types of tumors.
Posted at 11:21AM on Mar 14th 2007 by Gregory D. Pawelski